Windows 7 pre-orders began in Britain on July 15, and temporarily sold out on Amazon that same day. The OS immediately put Windows Vista to shame, selling more copies on Amazon in its first eight hours than Vista did in its entire pre-order period. In the past three months, the only currently available products to beat Windows 7 were Dan Brown novels. (People love a conspiracy theory.)

There are a couple of possible reasons why Windows 7 is doing so well before it even comes out of the gate. First, Microsoft enticed buyers with a considerable discount for Windows 7. In the US, upgrades to Windows 7 Home Premium sold for $50 between June 26 and July 11, and upgrades to Windows 7 Professional cost $100. In the UK, the discount for Home Premium was £49.99 instead of £79.99 from July 15 to August 14.

That's good enough incentive on its own, but I think a willingness from users to escape the horrors of Windows Vista sealed the deal. Windows 7 was viewed favourably even from its earliest public beta. An old Windows upgrade mentality - let the early adopters try the OS and work out all the kinks first - isn't as relevant this time around.

So, good for Microsoft and too bad for Harry Potter. But if it's any consolation to the people at Hogwarts, their launch parties are cooler.